Regulation and control method for two-stage SRB-PSB cooperative treatment of rare earth tail water

Abstract

The invention relates to the technical field of biological treatment of wastewater, in particular to a regulation and control method for two-stage SRB-PSB cooperative treatment of rare earth tail water. Firstly, specific pollutants are subjected to targeted passivation through a diammonium hydrogen phosphate-sodium tungstate complexing agent; then adopting a two-stage series SRB reactor, respectively adding sodium lactate and hydrogen microbubbles to realize electron gradient supply, and activating the biological membrane in combination with magnetic field pulse; in the PSB section, according to online sulfur valence state monitoring data, sulfur is directionally converted into elemental sulfur through 680nm / 550nm / 430nm three-stage intelligent light regulation and control; and finally, internal circulation of the system is constructed through double-substance backflow. According to the method, the synergistic effect that the removal rate of SO4 < 2-> is larger than 98% and the recovery rate of elemental sulfur is larger than 89% is achieved, and the treatment problem of ultrahigh-concentration and high-toxicity rare earth tail water is solved.

Description

Technical Field

[0001] This invention relates to the field of wastewater biological treatment technology, specifically to a control method for the synergistic treatment of rare earth wastewater using a two-stage SRB-PSB system. Background Technology

[0002] With the increasing intensity of rare earth resource mining, the sulfate concentration in tailings water from some mining areas has exceeded the conventional biological treatment threshold (>5000 mg / L), and contains characteristic associated radioactive elements such as thorium (Th) and uranium (U), as well as residual leaching agents (such as EDTA-type complexing agents). The existing two-stage SRB-PSB process has the following problems when treating such extreme water quality: Electron flux imbalance trap. When SO4 is influent... 2- At concentrations >5000 mg / L, the number of electrons required for SRB to reduce one unit of sulfate increases dramatically, whereas the traditional method based on COD / SO4... 2- The method of adding carbon sources at a specific ratio leads to two contradictions: if a high ratio (>2.5) is maintained, the excess carbon source cannot be fully consumed in the SRB stage and is preferentially utilized by the heterotrophic PSB in the PSB stage, competing with sulfide oxidation for electron acceptors, resulting in incomplete sulfide oxidation; if the ratio is reduced (<1.5), the SRB electron supply is insufficient, the sulfate reduction rate decreases, and the system's processing load is limited. This spatiotemporal mismatch between electron supply and consumption is a systemic defect that has not yet been clearly understood in this field.

[0003] "Silent suppression" of rare earth characteristic pollutants. Trace amounts of Th 4+ The inhibition of SRB by Th (<0.5 mg / L) and EDTA complexes (10-50 mg / L) is masked: 4+ EDTA binds to cell membrane phospholipids, altering their permeability, while EDTA also binds to essential trace elements (such as Fe) 2+ Co 2+ This indirectly affects enzyme activity. This inhibition is not significant in conventional water quality indicators (such as pH and ORP), but it leads to a slow and irreversible decline in SRB activity, and sudden failure after 3-4 weeks of operation.

[0004] The "black box" effect of sulfur valence state recovery. While existing technologies focus on sulfur speciation, they neglect the different valence states of sulfur (S). 2- S 0 S2O3 2- SO4 2- The real-time distribution and transformation kinetics of sulfur in the system are crucial. The lack of quantitative monitoring of the "sulfur flow" prevents the maximization of sulfur resource recovery.

[0005] The spatial heterogeneity of biofilms deteriorates. Under ultra-high loads, an extreme reducing microenvironment forms inside the SRB biofilm, leading to excessive accumulation of precipitates such as FeS within the membrane, blocking mass transfer channels and forming "dead membrane zones".

[0006] Currently, no technology can systematically solve the above problems. Therefore, there is an urgent need for a breakthrough method that can dynamically regulate electron flux, relieve the inhibition of characteristic pollutants, realize real-time monitoring and targeted conversion of sulfur valence state, and optimize the spatial structure of biofilms. Summary of the Invention

[0007] The technical problem to be solved by this invention is to provide a breakthrough method that can dynamically regulate electron flux, relieve the inhibition of characteristic pollutants, realize real-time monitoring and directional conversion of sulfur valence state, and optimize the spatial structure of biofilm.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A two-stage SRB-PSB synergistic treatment method for rare earth tailwater regulation includes the following steps: S1: Add diammonium hydrogen phosphate-sodium tungstate composite passivating agent to rare earth tailings water, and then separate solid and liquid after reaction; S2: The effluent from S1 is fed into a two-stage expanded granular sludge bed reactor connected in series. Sodium lactate is added in the first stage and hydrogen microbubbles are added in the second stage. At the same time, an intermittent rotating magnetic field is applied to activate the biofilm. S3: The effluent from S2 is fed into a photo-membrane coupled sequencing batch reactor and operated in a three-stage intelligent mode: Stage I uses 680nm light to promote S... 2- To S 0 Transformation, Stage II, using 550nm light to promote S 0 Accumulate and add nitrates, then in stage III, intermittently irradiate with 430nm ultraviolet light and start membrane filtration; S4: Part of the concentrated liquid from the S3 membrane filtration is returned to the front end of S2, and part of the permeate from the membrane filtration is returned to the rear end of S1.

[0009] Furthermore, in the above-mentioned two-stage SRB-PSB synergistic treatment method for rare earth tailwater, the dosage of the composite passivating agent in S1 is: diammonium hydrogen phosphate at n(PO4) 3- ):n(Th 4+ )=3:1-5:1, sodium tungstate according to n(WO4) 2- ):n(EDTA)=1:10-1:15.

[0010] Furthermore, in the above-mentioned two-stage SRB-PSB co-treatment method for rare earth wastewater, the operating parameters of the two-stage SRB reactors in S2 are: total HRT 36-54h, HRT ratio of the first stage to the second stage 2:1-2.5:1, and sodium lactate dosage controlled to achieve COD / SO4.2- =1.2-1.5, hydrogen dosage 0.5-1.0 L / g-SO4 2- .

[0011] Furthermore, in the above-mentioned two-stage SRB-PSB synergistic treatment method for rare earth tailwater, the carrier used in S2 is a three-layer composite carrier, consisting of, from the inside out: a porous magnetic Fe3O4@C microsphere core, a nano MoS2 intermediate layer, and a cationic polymer shell.

[0012] Furthermore, in the above-mentioned two-stage SRB-PSB co-treatment method for rare earth tailwater, the parameters of the intermittent rotating magnetic field in S2 are: magnetic field strength 100-300mT, frequency 1-5Hz, and running time 5-10 minutes / interval 6-8 hours.

[0013] Furthermore, in the above-mentioned two-stage SRB-PSB co-treatment method for rare earth tailwater, the time allocation of the three-stage intelligent mode in S3 is as follows: Stage I 0-8h, Stage II 8-16h, Stage III 16-24h; wherein the 430nm ultraviolet light in Stage III is intermittent irradiation, with the mode being irradiation for 30 minutes / 2 hours interval.

[0014] Furthermore, in the above-mentioned two-stage SRB-PSB synergistic treatment method for rare earth tailwater, step S3 also includes an online sulfur valence state monitoring system, which analyzes the sulfur valence state in real time based on UV-Vis multivariate spectroscopy. 2- S 0 S2O3 2- SO4 2- Concentration, monitoring data is used to provide feedback for adjusting light parameters and electron acceptor dosage at each stage.

[0015] Furthermore, in the above-mentioned two-stage SRB-PSB synergistic treatment method for rare earth tailwater, the recirculation ratio in step S4 is: S 0 The concentrate reflux ratio is 20%-30%, and the membrane filtration permeate reflux ratio is 50%-80%.

[0016] The beneficial effects of this invention are as follows: Chemical precipitation (PO4) 3- ) and Network Competition (WO4) 2- Dual-function preprocessing eliminates Th from the source. 4+ The "silencing inhibition" of EDTA creates a safe environment for subsequent biological processes. The SRB / PSB microbial community does not need to expend energy to resist toxicity and can devote itself to sulfate conversion, resulting in a long-term system activity retention rate of >92%.

[0017] The gradient electron supply strategy from sodium lactate to hydrogen achieves optimal spatiotemporal allocation of electron flux, avoiding carbon source waste and heterotrophic competition in the PSB segment. Combining a magnetic composite carrier with a pulsed magnetic field, it not only breaks down biofilm blockage but also enhances extracellular electron transfer through microcurrent effects, enabling the system to stably process SO4. 2- Extreme wastewater with concentrations as high as 10,000 mg / L.

[0018] Online monitoring of sulfur valence state based on UV-Vis spectroscopy, coupled with three-stage intelligent light modulation (680nm to 550nm to 430nm). Specific wavelengths of light sequentially activate different metabolic pathways of PSB, precisely directing sulfur flow towards elemental sulfur (S). 0 Synthesize S 0 Recovery rate increased from <70% to >89%, and purity was >85%.

[0019] S 0 Particle reflux enhances the stability of the SRB biofilm, while permeate reflux maintains the system's alkalinity and trace element balance. The dual reflux system forms an internal ecological cycle, reducing external reagent consumption by 40% and endowing the system with strong shock resistance and self-regulation capabilities. Detailed Implementation

[0020] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments.

[0021] The specific embodiments of the present invention relate to a regulation method for the synergistic treatment of rare earth tailwater using a two-stage SRB-PSB system, comprising the following steps: S1: High-concentration rare earth wastewater (SO4) 2- 5000-10000 mg / L, containing Th 4+ 0.1-0.8 mg / L, EDTA 10-50 mg / L) are introduced into the pretreatment tank, and diammonium hydrogen phosphate-sodium tungstate composite passivating agent is added, controlling the molar ratio n(PO4) 3- ):n(Th 4+ The ratio of sodium tungstate to sodium tungstate is 3:1-5:1, and the amount of sodium tungstate added is based on WO4. 2- EDTA = 1:10 (molar ratio); The reaction was carried out at a slow stirring speed (50-100 rpm) for 30-60 minutes to form Th4(PO4)4 precipitate and destroy the complexation of EDTA with trace metals. The effluent was then microfiltered (0.45μm) to remove the precipitate. The pH of the filtered water is adjusted to 6.8-7.2 and then introduced into the water distribution buffer tank; S2: The effluent from S1 is pumped into a two-stage series expanded granular sludge bed (EGSB) reactor (SRB-Ⅰ and SRB-Ⅱ) in an upflow manner. The reactor is loaded with a three-layer composite carrier: the core is a porous magnetic Fe3O4@C microsphere (2-3 mm in diameter), the middle layer is loaded with nano MoS2, and the outer layer is coated with a cationic polymer shell. Sodium lactate is continuously injected into the SRB-I inlet pipe to control COD1 / SO4. 2- Initial ratio = 1.2-1.5; Hydrogen (H2) microbubbles are pulsedly injected into the middle of SRB-II via a multi-point injection pump (H2 flow rate and influent SO4). 2- The load ratio is 0.5-1.0 L / g); the operating parameters are: temperature 35±1℃, HRT1 total = 36-48h (SRB-Ⅰ:SRB-Ⅱ = 2:1), and upflow velocity 5-8 m / h; Online sulfide-selective electrodes and NADH fluorescence probes were installed to monitor SRB metabolic activity; when SRB-II effluent was detected, S... 2- When the concentration is >250 mg / L and the NADH fluorescence intensity decreases by 20%, initiate the magnetic field-assisted pulse activation program: apply an intermittent rotating magnetic field to the reactor (100-300 mT, frequency 1-5 Hz, run for 5 minutes / 6-hour interval), and simultaneously supplement SRB-I with a trace element enhancer (containing Fe). 2+ Co 2+ Ni 2+ (0.1-0.5 mg / L each). S3: SRB-II effluent enters a photo-membrane coupled sequencing batch reactor (PMSBR), with the reactor containing: Spectrally tunable LED matrix (main wavelength: 430nm, 550nm, 680nm, intensity can be independently adjusted); Online monitoring system for sulfur valence state (based on UV-Vis multivariate analysis, real-time analysis of S) 2- S 0 S2O3 2- SO4 2- concentration); Transparent graphene / titanium dioxide composite membrane module (membrane pore size 0.1μm); Three-stage intelligent operation mode (24-hour cycle each): Phase I (0-8h): Turn on the 680nm LED (4000lux intensity), and control the ORP at -80±10mV and pH at 8.0±0.2 through micro-aeration (air-to-water ratio 1:100) to promote S 2- →S 0 Transformation; Phase II (8-16h): Turn on the 550nm LED (intensity 3000lux), stop aeration, and add nitrate as an electron acceptor (to control NO3). - -N=20-40mg / L), ORP rises to -30±10mV, promoting S 0 accumulation; Phase III (16-24h): Turn off all light sources, turn on 430nm LED UV mode (intensity 1000lux, irradiation for 30 minutes / 2 hours interval), and simultaneously start membrane filtration to collect S-containing substances. 0 Biological slurry; Operating parameters: temperature 30±1℃, HRT2=12-18h, sludge concentration (MLSS) maintained at 3000-5000mg / L; S4: The membrane filtration concentrate from PMSBR stage III (rich in S) 0 20%-30% of the biological particles are recycled back to the SRB-Ⅰ inlet pipe as a biological core enhancer; 50%-80% of the permeate from the PMSBR membrane filtration is recycled to the water distribution buffer tank to form an alkalinity and trace element cycle. The residual sludge from the PMSBR enters a sulfur cyclone separator to obtain elemental sulfur with a purity >85%.

[0022] Experimental Materials and Methods 1. Experimental setup Pretreatment unit: 50L PE mixing tank, equipped with a mechanical stirrer (0-500rpm adjustable) and a 0.45μm microfiltration membrane module; SRB section: Two-stage EGSB reactor with acrylic glass, SRB-Ⅰ effective volume 15L, SRB-Ⅱ effective volume 7.5L; PSB Section: 30L photo-membrane coupled sequencing batch reactor (custom-made, acrylic material); Control system: PLC automatic control cabinet, integrating all sensors and actuators; 2. Inoculation sludge and carrier SRB source: taken from the bottom sediment of a rare earth tailings pond in Jiangxi Province, treated with 6000 mg / L SO4. 2- Domestication takes 90 days; PSB bacterial source: taken from sulfur hot springs in Yunnan and acclimated with mixed sulfides for 60 days; Three-layer composite carrier: Custom-made by a professional company, parameters are as follows: Core: Fe3O4@C microspheres, diameter 2.5±0.3mm, specific surface area 320m² 2 / g; Middle layer: MoS2 nanosheets loaded with 8 wt% Outer layer: Chitosan-polyethyleneimine copolymer coating; 3. Simulated wastewater formulation, as shown in Table 1: Table 1 4. Analytical and testing methods All tests were performed according to the standards in Table 2, and each sample was measured in triplicate. Table 2 5. Experimental run cycle Start-up period: 30 days (gradually increasing load); Stabilization period: 30 days (data collection period); Impact test: 5 days (to verify stability); Total runtime: 65 days for both the examples and the comparative examples.

[0023] Example 1 Referring to the above specific implementation method, the regulation method for the two-stage SRB-PSB synergistic treatment of rare earth tailwater includes; In S1; Passivating agent addition: Diammonium hydrogen phosphate: 15.2 mg / L (as PO4) 3- (Calculate, n(P):n(Th)=4:1) Sodium tungstate: 6.0 mg / L (n(W):n(EDTA)=1:12) Reaction conditions: Stirring speed: 80 rpm; Reaction time: 45 min; Temperature: 25±2℃; Solid-liquid separation: Microfiltration membrane pore size: 0.45 μm; Filtration pressure: 0.1 MPa; pH adjustment: Adjust the pH to 7.0 ± 0.1 using 1M NaOH solution; In S2; Reactor loading: SRB-Ⅰ carrier loading: 40% (v / v), 6.0 L; SRB-II carrier loading: 40% (v / v), 3.0 L; Inoculation sludge concentration: 8.5 g VSS / L; Operating parameters: Total HRT: 36 h (SRB-Ⅰ 24 h, SRB-Ⅱ 12 h); Temperature: 35.0±0.5℃ (controlled by circulating water bath); Upflow velocity: 6.5 m / h; Carbon source addition: SRB-I sodium lactate: Dosage to achieve influent COD = 7800 mg / L (COD / SO4) 2- =1.3); SRB-II hydrogen: purity 99.9%, flow rate 0.8 L / h (based on 0.8 L / g SO4). 2- calculate); H2 microbubble generator: pore size 10μm, bubble diameter 50-100μm; Magnetic field activation procedure: Magnetic field strength: 200 mT (NdFeB permanent magnet array); Frequency: 3 Hz (achieved via a rotating mechanism); Operating mode: Run for 5 minutes, then repeat every 6 hours; Total activation time: 20 min / day; Micronutrient supplementation: FeSO4·7H2O: 0.3 mg Fe 2+ / L; CoCl2·6H2O: 0.15 mg Co 2+ / L; NiCl2·6H2O: 0.1 mg Ni 2+ / L; Dosing frequency: once a day, synchronized with magnetic field activation; In S3; Reactor configuration: Effective volume: 25 L; Membrane module: Graphene / TiO2 composite membrane, effective area 0.5 m² 2 ; Illumination system: Three-wavelength LED matrix (430nm / 550nm / 680nm independently controllable); Operating cycle (24h): Phase I (0-8h): Illumination: 680nm, intensity 4000±100 lux; Aeration: Micropore aeration, air-to-water ratio 1:100 (v / v); ORP control: -80±10 mV (aeration volume adjusted via PID); pH: 8.0±0.2 (automatic addition of 1M NaHCO3); Phase II (8-16 hours): Illumination: 550nm, intensity 3000±100 lux; Aeration: Stop; Nitrate addition: KNO3 solution, to control NO3. - -N=30±2 mg / L; ORP: -30±10 mV; Phase III (16-24h): Illumination: 430nm UV mode, intensity 1000±50 lux; Irradiation mode: On for 30 minutes, off for 2 hours (3 cycles in total); Membrane filtration: flux 15 L / m 2 ·h, runs for 6 hours; Concentration factor: 3x; Monitoring system: Ultraviolet-Vis spectrometer: wavelength range 200-800 nm, scanned every 5 minutes; PLS model: trained based on 1000 sets of standard samples, R 2 >0.995; Operating parameters: HRT: 15 h; Temperature: 30.0±0.5℃; MLSS: 4200±300 mg / L; S4 in; S 0 Concentrate reflux: Reflux ratio: 25%; Return point: SRB-Ⅰ inlet; Flow rate: 0.625 L / h (total influent 2.5 L / h); Permeate reflux: Reflux ratio: 65%; Return point: Pre-treated water distribution tank; Flow rate: 1.625 L / h; Sulfur recovery: Hydrocyclone separator: 50mm diameter, inlet pressure 0.3 MPa; Sulfur collection: once daily, dried and weighed.

[0024] The stable operation data is shown in Table 3: Table 3 Specific activity: expressed as sulfate reduction rate per unit VSS; Key performance indicators Sulfur mass balance (24-hour data on day 45): Total sulfur in influent (as S): 2000 g (6000 mg / L × 25L ÷ 6); Sulfur form in effluent: residual SO4 2- -S 28.3g, S2O3 2- -S 4.0g, total 32.3g; Recovered sulfur: 1780g of elemental sulfur, 187.7g of precipitated sulfur (FeS, etc.); Balance ratio: Σoutput / Σinput = 100.0%; Energy consumption analysis: Pretreatment unit: 0.15 kWh / m 3 ; SRB segment: 2.65 kWh / m 3 (Of which the magnetic field energy consumption is 0.25); PSB section: 1.20 kWh / m 3 (where illumination is 0.58 and membrane filtration is 0.42). Total: 4.00 kWh / m 3 ; Biomembrane characteristics: Biofilm thickness: SRB carrier 185±35μm, PSB carrier 210±40μm; Viable bacteria ratio: SRB biofilm 88.2%, PSB biofilm 76.5%; Extracellular polymeric substances (EPS): protein / polysaccharide = 1.8 ± 0.3.

[0025] Comparative Example 1 The solution described in Example 1 differs from the following: S1 stage: No diammonium hydrogen phosphate or sodium tungstate is added; the pH is adjusted to 7.0 using only NaOH. Other parameters: exactly the same as in Example 1.

[0026] Comparative Example 2 The solution described in Example 1 differs from the following: S2 stage: No H2 is added in SRB-II stage, and all sodium lactate is added in SRB-I stage to control the total COD / SO4 ratio. 2- -=2.0; H2-related equipment: Turn off the microbubble generator; Carbon source addition point: All carbon is added from the SRB-Ⅰ inlet.

[0027] Comparative Example 3 The solution described in Example 1 differs from the following: S2 stage: The magnetic field generator is turned off, and pulse activation is not performed; Trace elements: still added daily, but the method of addition is changed to continuous dripping; Carrier: A common carrier using the same material but without the Fe3O4 core.

[0028] Comparative Example 4 The solution described in Example 1 differs from the following: S3 stage: The PSB segment uses constant white LED (color temperature 6500K), intensity 3500 lux, 24h continuous illumination; Operating mode: The three-stage division is canceled, and the aeration is continuously controlled with ORP at around -100mV; Monitoring system: Turn off online monitoring of ultraviolet-visible spectra.

[0029] Comparative Example 5 The solution described in Example 1 differs from the following: S3 stage: The three-stage illumination mode is retained, but online sulfur valence state monitoring is cancelled; Operation control: The duration of each stage is fixed and is not adjusted based on sulfur speciation data; Nitrate dosage: fixed at 25 mg / L NO3 - -N, does not change with the form of sulfur.

[0030] Comparative Example 6 The solution described in Example 1 differs from the following: Phase S4: Cancel all backflows; Concentrate treatment: Directly fed into the sludge treatment unit; Permeate treatment: as the final effluent discharge; SRB segment alkalinity maintenance: switch to adding NaHCO3 (200mg / L).

[0031] Comparative Example 7 The solution described in Example 1 differs from the following: S2 stage: The two EGSB stages are merged into a single stage with a total volume of 22.5L; Carbon source addition: Sodium lactate and H2 are added simultaneously from the inlet (total COD / SO4) 2- =1.8, H2 flow rate 0.8 L / g SO4 2- ); HRT: 36h (same as the total HRT in the example).

[0032] Comparative Example 8 The solution described in Example 1 differs from the following: S1 stage: The dosage of diammonium hydrogen phosphate is halved (n(P):n(Th)=2:1); Sodium tungstate: dosage halved (n(W):n(EDTA)=1:24); Other: exactly the same as in Example 1.

[0033] Comparative Example 9 The solution described in Example 1 differs from the following: S3 phase: Phase I uses 620nm red light, and Phase II uses 470nm blue light; Light intensity: Adjusted to 4500 lux and 2500 lux respectively; Phase III: Remove 430nm ultraviolet light and replace it with membrane filtration under dark conditions.

[0034] Comparative Example 10 The solution described in Example 1 differs from the following: S2 carrier: using conventional polyurethane foam carrier (specific surface area 600 m²) 2 / g); S3 carrier: Ordinary polyethylene hollow fiber membrane is used; Non-magnetic: Cancel all magnetism-related configurations.

[0035] The experimental results are shown in Table 4: Table 4 SRB specific activity decay: the percentage decrease in specific activity after 60 days of operation relative to day 30; System stability index: A comprehensive index calculated based on factors such as effluent water quality fluctuation coefficient and activity decay rate (0-1, the higher the value, the more stable the system). Operating costs include chemicals, energy consumption, and maintenance, but exclude equipment depreciation.

[0036] Results analysis: Comparative Example 1 Result differences: Th 4+ The removal rate decreased from >99.9% to 84.2%, and the SRB activity decay increased from 7.5% to 42.3%. 2- Oxidation intermediate product S2O3 2- The accumulated amount increased from 12 mg / L to 85 mg / L.

[0037] Note: Characteristic pollutants (Th) 4+ Targeted passivation of SRB (such as EDTA) is a prerequisite for maintaining long-term SRB activity. Its "silencing inhibition" effect leads to a slow and irreversible decline in microbial activity and indirectly affects the sulfur form transformation pathway.

[0038] Comparative Example 2 vs. Comparative Example 1 Differences in results: S 0 The recovery rate decreased from 89.2% to 72.3%, S2O3 2- With a 10-fold increase in accumulated volume, operating costs increased by 37%.

[0039] Explanation: The dual carbon source gradient supply (sodium lactate → H2) solves the problem of spatiotemporal mismatch of electron flux. H2, as a clean electron donor, can avoid heterotrophic competition of PSB caused by excess organic carbon, which is the key to achieving sulfur-directed conversion.

[0040] Comparative Example 3 vs. Comparative Example 1 Results showed that SRB activity decreased from 7.5% to 18.7%, and biomembrane mass transfer efficiency decreased by 30%.

[0041] Explanation: Intermittent magnetic field activation can break the excessive deposition of FeS in the biomembrane, restore mass transfer channels, and maintain the healthy state of the biomembrane's spatial structure.

[0042] Comparative Example 4 vs. Comparative Example 1 Differences in results: S 0 The recovery rate plummeted from 89.2% to 65.8%, S2O3 2- The cumulative amount reached 185 mg / L.

[0043] Note: Different wavelengths of light have specific inducing effects on the PSB metabolic pathway. Three-stage intelligent light regulation (680nm→550nm→430nm) is the key to achieving S... 2- →S 0 The decisive factor for targeted transformation.

[0044] Comparative Example 5 vs. Comparative Example 1 Differences in results: S 0 The recovery rate dropped from 89.2% to 75.6%, and the system's ability to withstand load fluctuations decreased.

[0045] Note: Real-time sulfur valence state monitoring based on ultraviolet-visible spectroscopy is the foundation for achieving precise control; operation with fixed parameters cannot adapt to fluctuations in influent water quality.

[0046] Comparative Example 6: Comparative Example 1 Difference in results: The system stability index decreased from 0.95 to 0.79, requiring the addition of an alkalinity adjuster; Note: S 0 Particle reflux enhances biofilm stability, while permeate reflux maintains trace element balance. Material cycling is an important guarantee for the system's self-sustaining ability.

[0047] Comparative Example 7 vs. Comparative Example 1 Differences in results: SO4 2- The removal rate decreased from 98.6% to 93.5%, and the H2 utilization rate decreased from 92% to 45%.

[0048] Explanation: The two-stage series structure enables a gradient supply of electron donors, avoids competition between H2 and organic carbon, and improves electron transfer efficiency.

[0049] Comparative Example 8 vs. Comparative Example 1 Result differences: Th 4+ The removal rate decreased from >99.9% to 96.5%, and the EDTA removal rate decreased from 98.3% to 85.4%.

[0050] Note: PO4 3- :Th 4+ =4:1 and WO4²⁻:EDTA=1:12 are the optimal molar ratios. Insufficient addition cannot completely eliminate the inhibitory effect of characteristic pollutants.

[0051] Comparative Example 9 vs. Comparative Example 1 Differences in results: S 0 The recovery rate decreased from 89.2% to 82.3%, and the stage conversion efficiency decreased by 15%.

[0052] Note: 680nm light optimally activates sulfide oxidase systems, while 550nm light best promotes the sulfur polymerization process; wavelength selection is specific.

[0053] Comparative Example 10 vs. Comparative Example 1 Results showed that the SRB activity attenuation increased from 7.5% to 28.9%, S 0 The recovery rate decreased by 15.4%.

[0054] Note: The Fe3O4@C / MoS2 / cationic polymer trilayer structure not only provides a high specific surface area, but also enhances the performance of biofilms through multifunctional synergy such as magnetic response, catalytic active sites and heavy metal adsorption.

[0055] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A two-stage SRB-PSB synergistic treatment method for tail water of rare earth, characterized in that, The method comprises the following steps: S1: adding diammonium hydrogen phosphate-sodium tungstate composite passivation agent into rare earth tail water, and separating solid and liquid after reaction; S2: passing water from S1 into two-stage series expanded granular sludge bed reactors, adding sodium lactate in the first stage and hydrogen micro-bubbles in the second stage, and applying intermittent rotating magnetic field for biofilm activation; S3: The effluent of S2 is fed into a photo-membrane coupling sequencing batch reactor, which is operated in a three-stage intelligent mode: In stage I, S 2- accumulation is promoted by 680 nm light 0 0 accumulation is promoted by 550 nm light, and in stage III, intermittent irradiation by 430 nm ultraviolet light is started and membrane filtration is initiated;​ S4: returning part of the membrane filtration concentrated liquid from S3 to the front end of S2, and returning part of the membrane filtration permeate to the rear end of S1.

2. The method according to claim 1, wherein the method is characterized in that, The adding amount of the composite passivator in S1 is: diammonium hydrogen phosphate n(PO4 3- ):n(Th 4+ )=3:1-5:1, and sodium tungstate n(WO4 2- ):n(EDTA)=1:10-1:

15.

3. The method according to claim 1, wherein the method is characterized in that, The operation parameters of the two-stage SRB reactor in S2 are as follows: total HRT 36-54h, HRT ratio of the first stage to the second stage 2:1-2.5:1, sodium lactate dosage amount control COD / SO42- 2- =1.2-1.5, hydrogen dosage amount 0.5-1.0 L / g-SO42- 2- .

4. The method according to claim 1, wherein the method is characterized in that, The carrier used in S2 is a three-layer structure composite carrier, which comprises, from inside to outside, a porous magnetic Fe3O4@C microsphere core, a nano-MoS2 intermediate layer and a cationic polymer shell.

5. The method according to claim 1, wherein the method is characterized in that, The parameters of the intermittent rotating magnetic field in S2 are as follows: magnetic field strength 100-300 mT, frequency 1-5 Hz, and running time 5-10 minutes / interval 6-8 hours.

6. The method according to claim 1, wherein the method is characterized in that, The time distribution of the three-stage intelligent mode in S3 is as follows: stage I 0-8 h, stage II 8-16 h, and stage III 16-24 h; the 430 nm ultraviolet light in stage III is intermittently irradiated, and the mode is irradiation for 30 minutes / interval 2 hours.

7. The method according to claim 1, wherein the method is characterized in that, The S3 also contains a sulfur valence state online monitoring system, which analyzes S 2- , S 0 , S2O3 2- , SO4 2- concentration in real time based on UV-visible spectrum multivariate analysis, and the monitoring data are used for feedback adjustment of illumination parameters and electron acceptor dosage in each stage.

8. The method according to claim 1, wherein the method is characterized in that, The backflow ratio in S4 is: S 0 The backflow ratio of the concentrated solution is 20%-30%, and the backflow ratio of the membrane filtration permeate is 50%-80%.

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